Minimally invasive surgeries (e.g., percutaneous surgeries) account for an increasing number of medical procedures. These surgeries may result in less patient trauma and may yield a significant cost savings as a result of shorter hospitalization times and reduced therapy requirements, such as compared to open surgery. Percutaneous procedures can include endoscopic and catheter-based procedures, such as angioplasty (e.g., balloon angioplasty), stent delivery, and tissue ablation. In many of these procedures, pain, and even tissue damage, can be reduced or eliminated by targeting delivery of anesthesia to the nerves or other tissues adjacent to the vessel in which the procedure is taking place.
Examples of two treatments that could benefit from the controlled application of anesthetic to specific tissues include angioplasty and tissue ablation. For example, carotid angioplasty and stenting can result in stimulation of the carotid body, since acutely stretching or manipulating the carotid artery (which commonly occurs during angioplasty of this region) can stimulate the carotid body, which in turn can cause either bradycardia or hypotension. Patients with severe coronary artery disease or aortic stenosis may suffer concomitant cardiac arrest. Stent placement can also cause prolonged distention of the carotid artery resulting in continuous stimulation of the carotid sinus body, which may require treatment with vasopressor medications and require observation in an intensive care setting.
Similarly, the treatment of tissue within a vessel by ablation (e.g., using an ablation catheter), may deleteriously effect nearby tissue structures. Ablation of tissue from within the vessel lumen can heat even non-target tissue due to thermal diffusion from the application of energy (e.g., electrical energy). This heat may cause pain or trauma. The use anesthesia, particularly tumescent anesthesia, is one method of reducing the negative effects of endoluminal ablation. Tumescent anesthesia typically involves providing local anesthesia to a surgical site using dilute local anesthetic solution to both numb and “inflate” the tissue around the target ablation zone.
Another treatment that can benefit from minimally invasive surgery (e.g., percutaneous surgery) includes denervation of one or more nerve systems of a patient. Some studies have shown that denervation can be associated with improved physiological conditions in some patients. For example, denervation of at least a part of the renal sympathetic nervous system (SNS) can assist in improving hypertension. In addition, the carotid body can also play an important part in regulating hypertension and some studies have shown that altering the carotid body, such as altering either the sympathetic nerves or baroreceptors of the carotid body, can result in improved physiological results.
Hypertension can be a deadly disease when left untreated and is suffered by a growing number of people. Some studies have shown that sympathetic nerves, such as the renal SNS that runs through the adventitia surrounding renal arteries, can play a significant role in systemic hypertension. It is understood that hyperactivity of these nerves can cause renal hypertension. In addition, the carotid body, which is comprised of a group of chemoreceptors and baroreceptors located near the carotid artery bifurcation, can also play a significant role in hypertension. Hypertension can be treated with various drugs, such as antihypertensives, but recipients can experience a range of side effects, including increased risk of new-onset diabetes.